At first, the ketogenic diet sounds like heaven on earth.

“You eat lots of fat and protein, and you lose lots of weight!” What could be easier or more emjoyable for anyone who loves butter and steak?

However, when you dive headfirst into keto before taking a good, hard look, you may end up hitting your head on the rocks of frustration. “I didn’t realize I could never eat a potato or some ice cream! Potatoes are vegetables and ice cream is fat! This is crazy!”

You wouldn’t dream of jumping into a pool to swim the 400-meter butterfly event without knowing the rules – or without understanding the rigors of competitive swimming.

Starting a low-carbohydrate, high-fat diet like the keto diet (or similar low-carb diet plans like the Atkins diet) is easy if you’re prepared, but it can seem like torture if you’re not.

Let’s get you ready, step-by-step, to brave the waters of ketogenic eating.

When you open the fridge and aren’t sure what you can eat – or when you’re suffering through the first stages of the keto flu (more on that shortly) – that’s no time to start browsing low-carb diet websites or reading books.

A keto lifestyle is a substantial commitment, even though you should only be on the diet for the short term (three months is the maximum recommended by most nutritionists and dietitians). It only makes sense to understand the rules before the race begins. (We’ll stop with the swimming metaphors now.)

The Goals of a Keto Diet

Naturally, your ultimate goal is to lose a substantial amount of weight. But the real goals of limiting your macronutrient ratios to 5% carbohydrates, 20% protein and 75% fat are to put your body into ketosis and to keep it there.

On “normal” eating plans, the body turns carbohydrate intake into the glucose it uses for energy. (You may know glucose as blood sugar.) But ketosis isn’t a “normal” metabolic state. It’s induced when the body can’t get glucose and starts manufacturing ketone bodies (ketones for short) as a replacement energy source.

When you follow a keto meal plan and limit your carb intake, the body enters a state of ketosis so it can produce and use ketones. Why is that important? Because the body creates ketones by burning your stored body fat. Once you begin to burn fat you’ll quickly start to lose weight. 

Deviating from a keto diet causes the body to “fall out” of ketosis, and the fat burning and weight loss stops. You might even gain the weight right back. So the real goals are to get into ketosis, and then to stay there. You do that by eating the right foods.

What You Can and Can’t Eat

The guidelines for a keto diet plan are pretty straightforward once you’ve gotten a good handle on them.

We won’t spend pages and pages explaining them all now, but here’s a quick rundown. (We have full articles elsewhere on our site explaining the keto diet, listing all of the major keto diet foods, and detailing a keto shopping list.)

The most important rule is that you have to keep carbs at or below 5% of your total daily calorie intake. That’s around 20 grams of carbs (net carbs, not counting dietary fiber) for most people. And the way to get there is to stay away from grains and starches. In a nutshell, that means no bread, pasta, potatoes, bakery goods, soda, juice or fast food. Most packaged products are out as well, since they’re likely to have added carbs.

That basically leaves naturally low-carb foods like protein, veggies that grow above ground, and healthy fats. Before starting keto, you should spend some time with the lists we mentioned above to be sure you know what’s on the “naughty” and “nice” lists. Once you have a complete feel for what you can and can’t eat, it makes keto dieting a lot easier.

Be Sure Keto Is Right for You

The keto diet is safe for most people. But even if you’re fully committed to keto eating, the diet may still not be the right choice for you. People with gallbladder or kidney issues, hypothyroidism, or eating disorders can easily see their conditions worsen when following keto guidelines. (Intermittent fasting mixed with keto can be an subject worth pursuing if you’re prone to overeating.) Women who are pregnant or nursing should also wait to start keto.

The keto diet usually helps most of those who have type 2 diabetes, but type 1 and type 2 diabetics may each run into problems on keto. If you have concerns about diabetes and keto, check with your doctor before starting.

Most people starting a diet know better than to leave a chocolate layer cake on the counter or a gallon of ice cream in the freezer. Temptation is a dieter’s worst enemy.

Similarly, you should take time to clear your kitchen shelves, refrigerator and pantry of everything but keto-friendly foods before starting the diet. It’s all too easy to grab a box of spaghetti or a frozen pizza when you get home late from work, but that will undo all the hard work you’ve done getting into ketosis.

Also do a sweep to get rid of (or hide) other foods which can knock you off your diet before you can even think about whether they’re OK for keto. Bottled salad dressings, canned beans, sweet potatoes, vegetable oils – there are many foods hiding in the average kitchen which may seem innocuous but aren’t acceptable keto foods.